Fuel distribution system



June 10, 1952 H. HERSCH 2,599,915

FUEL DISTRIBUTION SYSTEM 1 Filed July 23, 1947 2 sums-swam 1 IN V ENTOR. BY A m rm J$MANIIIIIIVL 4 y ML 'lw June 10, 1952 sc 2,599,915

FUEL DISTRIBUTION SYSTEM Filed July 23, 1947 2 SHEETSSHEET 2.l/II//////////////- I .,1/II/////////////J IN V N TOR.

3 7 /WW 9W WW Patented June 10, 1952 iilvntidn "riates be inteiii'al 'jcemblistion the development of the interii'al com-bustier;fenceledfeinmi jerjthe distiiibution gyseemq I K The p en I l-" fiw iheb w ys em 'meeereiegbecenie widely aeeepteepe 'ause ex it's .tibn eneee. ,ttevine he eele ve e fi l m 1mpr oveg distribution systemwiththeinfiake i fiel W fifidrs; e w h zieme a mae 'nmem z eiee forthorie embodiment of my improved fuel t, r;ib uj;iog; system i andemploying a diaphrag m aeafiedzv v a, 7.. e. .v

Figure 3 is a vievvthrough'the line 33 of Fig- QZ; g

V Figure l is a "further illustration of the principle of my inventionin which an alternative type valve'is emp1oyed; and v Figure5' is a:ball-check type of valve and idle system which may be employedes a fuelvalve in my's'ystem.

WithTeference to the Figure 1 of the 'dr'a'wmgs, I illus't relt efaporigidn or a'dynndr block 25 having 'a plurality of cylifidefs. In thisFigure 1, the opexeitionbf emymwo cylinders 22 and "23 is cbfisidred,because phe ar sufficient; to set ferm' -fi e principle er my mveneien.The cy1- "ifider-blddk =25 may have any ri'u'mber qr cylinwiefi i "i iljwv e t e us a o r. de n id:- jace pyl in'de r s, for example thejpylipdezi s ju feifiel fi fwil'l fiavefiheiii' intakeportin 9, common1;:118' 1 b, pa mp r a 9. Thelgefore the inteike'velvee -positiofie1adjgeentoigeanofiheii, Whei eae egihaiise VBIIYVGJSVQH 'areplaced at. the 'e'xtrerneipdsme 'Iqgl onventionefl design,the xhaustvalves jz l apje place-ii ert; 115m: extreme po s it'ions'in "order fiojdisperjse enema from the ek'hau'st more even1y, jaf1flfp1fevent eeensramg heat from tvvo exhailst valves, In m impmved, fueldilst'iibepion sy tm I hav'e i i aken advantage of the id'- "tig'jn d fith two intake va1ves 20 Within one akfhezfpder ge -n order m redu e themini- .per o f ,'p2 t}s ;equi; ed. to disltii b ufie "the fiil. i i cwvev jer, the location of the intake 5nd ex hmi st ise- 2 e f' lia yfi ft fil i iieejop epg ine {I rgo way afiieefis the principle of nv e i eand my in ti may be "aim d Tu ,eia e s enq ng an m y be a plied t anygles i g'n 9; engine whether the irifiake valves 20 age 50 located ae totake :advajiitage of fife i qiacemiq aeo rnoe o A II 1 we ifigure 1, 1 havevillqstra ted a boffiioh of a r imalge gnggifolg l0, In my fueldistribution F w...? m?2 f9ll .3 i i fact only an ai r d et. an '5 u tub an a v fle he when.-

fioxial in'fiak 'ziilfii'fold only for the purpose of with'inlthe,manifold I0.

basic principle of operation for my improved system, and in that figurethe manifold is repre sented by a straight length of conduit 34.

valve II is positioned near an entry end of the conduit 34 and the otherend of the conduit 34 goes directly to the intake port of the cylinders.In a six-cylinder engine, for example, three devices as illustrated inthe Figure 1 could be used to operate the engine. However, if an aircleaner is .to be employed, three cleaners would be re.- quired .ifstraight lengths of conduit were to be used inplace of the unitarymanifold ID illustrated in the Figure 1. Furthermore, three synchronizedvalves I I would be required in the use of a straight. conduit aspictured in the Figure 2, in place of the one as illustrated in theFigure 1. These are matters of design, and in'no way pertain to theprinciple of operation of my invention.

As indicated, the Figure 2 is provided to set forth one exampleemploying the principle of my invention. In the Figure 2, Iillustrate'the venturi I2, a diaphragm device I3, a valve I4,

anda fuel metering system I5. A conduit I6' extends from the throat ofthe'venturi I2 to the upper chamber II of the diaphragm device I3.

'A branch arm I8 leads from the conduit I6 to the valve IL. Thebutterfly valve I I is mechanically interconnected with the meteringdevice I5,

and both members are attached to a manually controlled accelerator inorder that the-quantity of air and the quantity of liquid fuel may beproportionately increased and decreased to control the speed-of theinternal combustion engine.

As illustrated in the Figure l of the drawing,

.I locate the venturi I2 as close to the intake port ofthe internalcombustion engine as is practical for operation under natural physicalconditions. Therefore, when the pistons of the engine draw a charge ofair, and only when the pistons draw a charge of air, the air will rushrapidly through the venturi I2, as well as around the venturi Thissimple yet fundamental fact is the key to the success of my distributionsystem. In the Figure 2, the intake valves and pistons are notillustrated, but it is understood that the venturi I2 is to be placed asclose. to the intake ports as practical.

Also, I have placed the venturi to take advantage of the most directmovement of airto the cylinders. In an engine having an intake portbelow the valves, this position is at the top of the conduitconductingthe air. Air, like electricity, tends-to follow the path ofleast resistance. In an overhead valve system, therefore, the venturiwould be placed at the bottom of the conduit.

Furthermore, the butterfly valve tends todirect In the Figure 2 it willbe seen that the butterfly "charge of air-at the same time.

turi in the Figure 2. When air is drawn into a cylinder, air will passthrough the venturi I2 as well as around the venturi I2; However, themovement of air through the conduit 34 into a :particular intake port isnot constant, but will only be in motion during the intake period of thework cycle. Therefore, the low pressure area at the throat of theventuri I2 will exist only during the periods in which the cylindersserved are drawing a charge stroke. However, in the manifold typeconduit I0 illustrated in the Figure 1, air will be drawn into theentrance port of the manifold I0 almost continuously, because air. willbe drawn by at least one ofv the multiple cylinders of the engine blockat all times. Thereafter, the air drawn through the entrance port pastthe butterfly valve will be directed in one of the several branch armsof the manifold Ill. Therefore, considering each branch armindividually, the movement'of air in a particular branch arm will besubstantially as described in connection with the conduit 34 of Figure2. That is, in Figure l the branch arm of the mamfold I0 serving thecylinders 22 and 23 will have a movement of air therethrough only whenthe cylinder 22 or the cylinder 23 is drawing-a charge stroke. At othertimes the movement of air in the branch arm serving the cylinders 22 and23 will be nil. Consequently, the low pressure area at the throat of theventuri I2 in the branch arm of the manifold I0 serving the cylinders 22and 23 will be in evidence only during the period when either thecylinder 22 or 23 is drawing a charge of air. Of course, in theconventional firing arrangement 'of an internal combustion engine, thecylinders 22 and 23 will never be drawing a Therefore, the one brancharm is able to serve both of the cylinders 22 and 23.

When the low pressure area is produced in the venturi I2.as a charge ofair is drawn into a cylinder, a low pressure area will be produced inthe conduit I6 and the branch arm 'I8.- Consequently, the low pressurearea will be produced in the top chamber portion II of the diaphragmdevice I3; Ordinarily, difierential of pressure is produced between the.throat of'the venturi I2 and the conduit 34 to operate the diaphragm I9,and therefore it would be sufficient to connect the lower chamber 24 ofthe diaphragm device I3 to the conduit 34 posterior to the butterflyvalve II. It would then appear that a suflicient-difierential ofpressure would be produced on the diaphragm I9 by the action of theventuri I2 on the upper chamber II to move the diaphragm I9- by such anarrangement. HowevenI have found that the differential of pressurebetween the throat of the venturi, and the conduit 34 proper, will ,varyconsiderably from low speed to high speed operation 'of the engine, andtherefore I have provided additional means to close the 'valve rapidlyin. responseto cessation of the intake charge. into .the cylinder.. Whenthe cylinder begins to draw a charge 'of air, the valve I 4 should be,opened immediately to allow gasoline to pass through'the valve Hand thebranch arm I8 into theconduit I6 and into the throat of the venturi I2.Thegasoline then willlbe impactedwith a rapidly rushing stream-ofair'andcarried direct ly into the closely adjacent intakeport. "At theend of the intake stroke, however, the valve H should' belclosedimmediately tostop the flow of gasoline. Otherwise, an excess offuel-would be carried-into the Venturi I 2,- andthis excess-f fuel wouldcollect in the bottom of the" conduit 34-as raw liquid fuel. This is thecondition which, exists in present type-carburetion' devices, and:is'to-beavoided forv good fuel distribution. In fact, much attentionhas been given to ways and means to recollect precipitated gasoline inthe present air suspension carburetor devices. I-ha-ve-made thediaphragm device of my a'rrangement to take advantage of the change inairspeedtravel within the conduit 34. N0 raw fuel is' ever deposited inthe conduit 34. -Only the amount of fuel actually required is drawn intoI the Venturi.

illustrate-a conduit 26 leading from the lower chamber 24 of thediaphragm device- I3 through a Venturi valvedevice 21, The Venturi valvedevice fl islccated in-=any convenient position relative to the conduit34' between-the intake port andthe butterfly valve II. A small opening"is.v provided. through i the wall of the conduit :34 to; the interior ofthe device 21. It'willbe noted from -the Figure /2 of the drawing, thatthe 'Yenturivalve device 21 is formedwith internal surfaces intheconventional Venturidesign, :and

the: end-of the :conduit 26 is positioned at the low; pressure throatarea of theV-enturidevice 21.

A small opening 29 is provided to connect the interior of the device 21with the atmosphere.

The area of hole 29- is preferably larger-than;- the .bridge 30 1sadapted to be secured to the internal surface oftheconduit 34 by meansof any suitable attachment device, for example thescrews 31 illustratedin-the Figure 3 of the drawing. The bridgeimember 30 has a clearance 32through vvhichairmaypass from the front to the back thereof in relationto the flow of air in the-conduit 34, The clearance -32 is only a fewthousandths of-an inch and the air trapped by the leading edge 33of thebridge 30 willpass very rapidlyth-rough the clearance 32 past the faceofthenopening 28. Those familiar with the science of physics willunderstand thatsuch a rushtof air through the clearance 32 willpassbytheflopening Z-B so'rapidly that substantially none ,of the air willpass out through the opening28 to, the interior of the Venturi device 21which "is .-substantially at atmospheric pressure. On theother'hand,even though the pressure within the conduit will be somewhat, lower thanatmospheric pressure due to the rapid movement of air therethrough, theamount of air effectively passing throughthe small opening 29throughfthe Venturi valve device 21 and into the conduit through theopening 28 will-be negligible'com'pared to the volume of air passingthrough conduit 34 during the intakestroke. The opening .9 willmaintain-the pressure in the tube 2 6 1at substantially atmosphericpressure during theintakestroke, thus the pressure in'thetop chamber I!will be less-thanthe pressure inethe bottom chamber 24, Thiscausesdiaphragm Hi to :snap upwardly and open needle valve HI. However at theend of the intake strokethe= rush of air -will-ccease,- and there willbe a--short,.,-period -of time required bei'ore thei-pressure within theconduit 34 can build up towards atmospheric "pressureby air movingir'ito the interior thereof to replace the air drawn intothe:cyliridersiduring' i-the; charge stroke. Duringthis period air will belable to 'rush through theopeningna into the interior of the Venturivalve "device 1:21am

through-the opening "into the low pre'ssureare'a within-thei'conduit u.Of-courseisuchia rush of air at'the throat: of; the :Venturi valveidevic, '2 i pas't the endibfl the :conduit 5 2 6" produces i owpressure: area attthe epening ofthei conduit 6. (lonsequentlmfia lowfipressure 5 area will he prodced: inithelower chamber u anthe -"diaphragmdevice t3.

At the -end or -theintake-stroke; the-46w pressure a-i-ea within tl-iethroat -of the ave-titan l "i 2 Will -be troirenbecauseof the-suddenstoppage orzaiepassifig tnrcugn the 'venturr 12, and' there'- toreaimWill te'nd -td"rush through the "enrich-lit F6 to the upper 'chainberjl'l. 'The s'iini-iltaneou ncreaseora pressure 'witiiin the chamber 1and the decrease of pressure within the chamber- 24, willcausethediaphragm Hi to snap downwardly and close the valve l4. Conversely,vvhen -a charge of air is being drawn rapidly through the conduit 34 thediaphragm I9 will be "quickly pushed upwardly'to open the valve l4 bythe production of 'a' low pressure in the upper chainber 11, "and"atmospheric pressure in the lower chamber 24 produced by air passing'throu'gh' -the opening 29 and into the-end of the conduit-"26. Aspreviously described, the passage of air through the clearance -32 willsubstantially-block o'fi the' opening-28, but' this will not prevent-airpassing-through; the opening 29' and up intothe conduit 26.

The low :pressure area at -the throat of the venturi 1 l 2 in I theembod-imeiit illustrated a in the Figure 2 of the drawings, serves adouble purpose The lowpressure areanot only serves to operate thediaphragm l9 described, but produces a high vacuum on the branch arm [Band consequently vvi-ll tend to draw gasolinethrough ther'valve M i'romthe'metering device 15. "That is, 1 the conduits l6 and l8 areinterconnected andenter the-throat of'the venturi l2. A--low pressure inthe throat of 1 the Venturi, therefore, results'in a corresponding lowpressure'in coriduits I6 and l8, and also inthe chamber l1. Therefore,this low pressure produced I in the throat 'of venturi reduces th'epressure in chamber l'I-and operates the diaphragm I'B' and the needlevalve. Operation of the 'needle valve 'will open aipassageway tointerconnect iconduit l8 and metering; device IS. The pressure,- asstated, incon'duiti L8 is low when'conduit I6 is. low. The pressure onmetering device 15 is atmospheric,

or high. Therefore, a pressure differential is produced which will forcegasoline to flow through:- conduit l8"to the s'ouree of the lowpressuregnamely', the throat o'f venturi' l2. Ga solinepassin'g irom themetering device through thevalve will thereforeenterthe "conduit [6 andbe drawn-into the throat of the Venturi I 2. Upon entering thethroat ofthe Venturi l2, the gasolinewill be' imp'acted by an extremely rapidmovement-of air, and therefore will be finely dispersed. Furthermore,this finely dispersed gaso-i line is carried from the 'endof the Venturil2 andi-rito-the cylinder 22 or 23 before it has any opportunity to:precipitate from the air. Therefore,substantially every atom of thegasoline is carried into. the cylinder, and" the wal'l's of the conduitiil-fwill befoundto' be completely dry-at all stages of operation of theengine; whether hotv or cold. Furthermora'it is unnecessary to provideany hot spot in order to heat the air passing through the venturi l2 tothereby vaporize the gasoline. Such powerwasting practices arecompletely avoided in my improved fuel distribution system. The air; isdrawn through the venturi l2 completely unheated.v Consequently, becausecold air is more dense and. compact than heated air, the charge of airgoing into an individual cylinder will contain a greater amount ofoxygen than hot air would have. This is known as an increase involumetric efficiency. As a result, an, internal combustion engineoperating with my improved fuel distribution system will have greatlyincreased torque and power 'due to the increased volumetric efficiencyproduced by my cold air supply tothe engine. 1 Furthermore, an engineoperating, with my improved fuel dis.- tribution system will be found tooperate at a marked decrease in temperature because of the coolingeffects of the cold air entering the cylinder. V l

. With my improved distribution system, each cylinder receives an equalamount of fuel re- 7 g-ardless of its position. This is a distinctadvantage over present type carburetor systems having one centralcarburetor'and dependent upon air suspension. Conventional carburetorsystems do not equally distribute the fuel Some attempt has been made tocorrect'for theim proper distribution by using more than one carburetor.In fact, some attempt has been made to supply each cylinder with acomplete carburetor. Even this expensive expedient has failed, becausethe location of the venturi of ordinary carburetors relative to thebutterflyvalve fails to make the venturi instantly responsive .to airintake, and further, the venturi in conventional carburetors is spacedaway from the cylinders, and more dependency is placed upon suspensionof the fuel in air to carry the fuel into the carburetor. 1

In the Figure 4 I illustrate a ball-check valve system which I havefound to be simple to conistruct, and which has certain advantages ofoperation.: I have placed ball-check valves 41 in the lines, 46 leadingto the individual venturis. These ball-check valves '41 are for theprimary purpose of stopping'one venturi from drawing fuel from another,or drawing air through the other lines 48. Thesp'rings used are only ofsufii cient tension to overcome gravity andvibration tending to unseatthe ball; The mainvalving action is provided" by ball check valve 50having a spring 5| holdinga .ball 52 seated to prevent the passage offuel through the check valve 50. The spring 5i is of substantiallygreater tension than the springs in the, check valve 41, and thereforewill hold the ball 52 seated until the individual venturi devicesproduce a pressure differential great enough to overcome the tensionofthe spring 5!. The spring 5| is normally" provided of a tensionsufficient to resist the pressure differential at cranking and lowrunning speeds.

Fuel is supplied for the engine at thelow running speed, and forcranking starting, by an idle fuel line 53. The line 53 is of a smallinside diameter, and can supply only sufiicient'fuel for a low -speedoperation of the internal. combustion engine. The line 53 enters thefuel'distrib'ution system posterior to the ball 52, and isthereforeunaffected by the ball 52. During operation, therefore, the systemillustratedin Figure 4 will supply fuel to the engine through the idlefuel 8 line 53 during cranking and low running speed of the internalcombustionengine, and will supply fuel through both the valve 52 and theidle fuel line 53 during normal running speed of the engine. Thus, anexcess of fuel is prevented from pressing against the balls of the checkvalves 41 duringlow speed operation of the engine, and consequently willprevent any possibility of gasoline seeping around the balls and intothe individual venturis which are at that time inoperative.

In the Figure 5 of the drawings I illustrate an alternate type of mainvalve and idle supply valve which may be used in place of the ball checkvalve 50 and idle fuel line 53 illustrated in the Figure 4. The mainvalving action is provided by a ballcheck valve 35 for running speedsand a by-pass 38 for cranking and low speed operation. The check valve35 contains a conventional ball 36 and a spring 31. Fuel is fed to thevalve 35 through a fuel line 45 from a source at atmospheric pressure.Fuel is distributed from the valve 35 through feeder lines 46 to thevarious Venturi devices at the intake port. It is of course under stoodthat the pressure differential between the lines 46 and the lines 45,during cranking and low speed operation of the engine, will be somewhatlower than durin running operation of the engine. This is true becausethe amountof air passing through the venturi is quite small and thespeed of the air travel is quite low. The spring 3! is thereforeprovided with sufficient tension to maintain the ball 36 seated toprevent fuelpassage therethrough during the cranking and low speedoperations of the engine. I v 7 l l 'During low speed operation of theengine and cranking periods for starting the engine, I provide fuel bymeans of the by-pass valve 38. The bypass valve 38 is provided with aball 39 and a spring 40 substantially as illustrated in the valve 35.However, the spring 40 is of a. much-weaker tension than the spring 37.Consequently, cranking and low speed operation of the engine will unseatthe ball 39 and allow fuel to pass by the bal139. The amount of fuelallowed to so pass may be conveniently controlled by any suitable means,such for example as the adjustment screw 4|. A fuel line 42 extends fromthe top of the valve 38 into the top of the valve 35 as illustrated. Aneedle valve pin 43 maybe positioned to, move with the ball 36, andtherefore when the ball-36 is unseated to allow fuel to pass thereby,the needle valve pin 43 will close the line 42 and stop the passage offuel from'theby-pass valve 38. Therefore, as the internal combustionengine is cranked to start the operation ofithe engine-the normal lowpressure produced in the venturi will draw through the lines 46 andunseat theball 39 in the by-pass valve 38. Suflicient fuel will bepassed by the ball 39 to start'operationof the engine. Further, if theengine is runonly at low speeds, the degree of vacuum will be largeenough to keep the ball 39 unseated and pass sumcient fuel for low-speedoperation of the engine. However, as the speed of the engineincreases,.the degree of pressure differential will increase. When thespeed of the engine reaches this degree,.the ball 36 will overcome theresistance of the spring 31, and allow fuel to pass through the valve 35to supply the engine for high-speed operation. This combination of themain valve 35 and theby-pass valve 38 serves to stop the flow of fuelwhen it is not required, and allow the flow of fuel at the proper timesas dictated by the various Venturi devices. That is, the valve systemillustrated in 911; the Figure is one of many which may be used tocontrol the now of fuel to theengine, but is dependent :upon my improvedVenturi placement for correct timing of the fuel supply. Generally, thevalve mechanism as illustrated in Figure '5 in which three branch arms46 are illustrated, will be used with a six-cylinder engine. Therefore,the flow of fuel through the valve will be substantially constantbecause'one of thesix cylinders will always be drawing fuel. However,the placement of the Venturi device at the intake ports of the cylinderwill direct the fuel through the-particular line 46 at the correcttnne-*for-'distribution into the cylinder which is at that time drawingair. In other words, my Venturi placement is the timing and distributiondevice which makes my system practical. Fuel will be drawn through aparticular branch arm 46 only when air is being drawn into a cylinderserved by a particular Venturi device. Furthermore, this fuel isdirected, directly into the intake-port, and does not have to beconducted through a long -mani fold tubein suspension with air.Therefore,there 10 said'air intake duct, a fuel line extendingfrom saidmetering means to the throat of each Venturi means, and ball-check meansdisposed in the fuel line to each venturi, whereby a predetermined-rateof air flow through a venturi will produce a predetermined low pressureon said fuel line'to unseat-said ball-check and pass a metered amount offuel from said metering device to said I, venturi.-

is :no chanceof fuel precipitation forthe air.

Furthermore, there is no overloading of raw fuel at the entranceportwaiting'its chance to get into a cylinder. The fuel is supplied onlywhen the cylinder is drawing a charge.

Although "I have described myinvention in its preferred form with acertain degree of particularity, it is understood'that the presentdisclosure of the preferred form has been made only by way of exampleand that numerous changes in the details of construction and thecombination and arrangement of parts may be resorted to withoutdeparting from the spirit and the .scopeof the invention as hereinafterclaimed.

What is claimed is:

1. In combination with an internal combustion engine having at least anintake port, thexprovisionof an air conduit for said port, first'Venturi means in said conduit, second Venturi means having an entryopening and exit opening with azlow pressure producing throat areatherebetween,.-said exit opening extending-from the interior of thesecond Venturi device into the interior of the conduit, said entryopening extending. to atmosphere, a diaphragm device having a flexiblediaphragm separating a first chamber and a second chamber, tube meansextending from the throat area of said first venturi to the firstchamber, tube means extending from the throat area of the second venturito the second chamber, and fuel valve means operable by movement of saidseparating diaphragm, said first venturi serving to produce adifferential of pressure between said first and second diaphragmchambers upon movement of air through said conduit and first venturi tosaid engine and thereby operate said valve means to allow fuel to beadmitted to said engine, and said second venturi servin to produce adiiferential of pressure between said second and first diaphragmchambers upon stoppage of air movement through said conduit to saidengine and thereby operate said valve means to stop fuel passage to saidengine.

2. A fuel distribution and timing system for a multiple cylinderinternal combustion engine having a plurality of intake ports,comprising an air intake duct having a plurality of branch arms, onesuch branch arm leading to each intake port, Venturi means in eachbranch arm adjacent said intake port, fuel metering means, means tocontrol the volume of air flow into the engine through 3.In'combination' with an internal combustion engine having aplurality ofintake ports,the provision of a Venturi device adjacent each port, afuelline to' the low pressure producing throat area of each- Venturi device,a ball-check valve in each fuel line, said ball-check valves havinglight weight seating valves capable'of being actuated to unseat'thevalve-under a pressure differential in the fuel line'produced by airpassingthrough said Venturi device in cranking the engine and at lowrunning speed of the engine, a master ball-check valve, each said fuelline extending to the master ball-check valve, said master ball-checkvalve having aheavy seating spring capable of being unseated only byapressure differential substantiallygreater than the pressuredifferential sulficientto operate the fuel line ball-checkvalves, andfuel by-pass means to pass fuel'by the master ball-check during crankingandlow speed opera tion'of the engine;

4. A fuel distribution and timing system for an internal combustionengine having at least 'anin' take port'and an intake duct,comprising-a-Ven turi member in said duct adjacent to said intake port,ball-check fuel Valve-means operable by a differential of pressure,conduit means leading from'the throat of 'said'venturi tosaid'ball-check valve means for producing a low pressure area to operatesaid ball-check valve means and conduct fuel from said valve means tosaid intake duct, and means to meter the flow of fuel through said fuelball-check valve means.

5; In combination with an internal combustion engine having at least anintake port, the provision-of an air conduit for said port, firstpressure differential means in said conduit, second .pressuredifferential means havingan entry'opening and exit opening,' said exit.opening extending from the interior of the second pressure differen tialdevice into the interior of the conduit, said entry opening extending toatmosphere, 9. diaphragm device having a flexible diaphragm separating afirst chamber and a second chamber, tube means extending from the throatarea of said first pressure differential to the first chamber, tubemeans extending from the throat area, of the second pressuredifferential to the second chamber, and fuel valve means operable bymovement of said separating diaphragm, said first pressure differentialserving to produce a dilferential of pressure between said first andsecond diaphragm chambers upon movement of air through said conduit andfirst pressure differential to said engine and thereby operate saidvalve means to allow fuel to be admitted to said engine, and said secondpressure dilferential serving to produce a differential of pressurebetween said second and first diaphragm chambers upon stoppage of airmovement through said conduit to said engine and thereby operate saidvalve means to stop fuel passage to said engine.

6. In combination with an internal combustion engine having at least anintake port, the provision of an air conduit for said port, air fiowcontrol means in said conduit, first Venturi means in said conduitbetween said port and said air flow control, second Venturi means havingan entry opening and exit opening with a low pressure producing throatarea therebetween, said exit opening extending from the interior of thesecond Venturi device into the interior of the conduit between said portand said air flow control, said entry opening extending to atmosphere,airfoil bridge means positioned on the interior of said conduit andproviding a narrow air passageway past said exit opening, a diaphragmdevice having a flexible diaphragm separating a first chamber andasecond chamber, tube means extending from the throat area of said firstventuri to the first chamber, tube means extending from the throat areaof the second venturi to the second chamber, and fuel valve meansoperable by movementof said separating diaphragm, said first venturiserving to produce a diflerential of pressure between said first andsecond diaphragm chambers upon movement of air through said conduit andfirst venturi to said engine and thereby operate said valve means toallow fuel to be admitted tosaid engine, and said second venturi servingto produce a differential of pressure between said second and firstdiaphragm chambers upon stoppage of air movement through said conduit tosaid engine and thereby operate said valve means to stop fuel passage tosaid engine.

7. In combination with an internal combustion engine having at least anintake port, the provision of an air conduit of definite cross-sectionalarea for. said port, air flow control means in said conduit, Venturimeans in said conduit between said port and said air flow control, saidVenturi means having cross-sectional area less than said definitecross-sectional area, of the air conduit thereby providing a path forpart of the air through the venturi and also a .path for part of the airalongside and outside of the venturi, a diaphragm device having aflexible diaphragm separating a first chamber and a second chamber, tubemeans extending from the throat area of said venturi to the firstchamber, and fuel valve means operable by movement of said separatingdiaphragm, said venturi serving to produce a differential of pressurebetween said first and second diaphragm chambers upon movement of airthrough said conduit and venturi to said engine and thereby operate saidvalve means to allow fuel to be admitted to said engine.

8. In combination with an internal combustion engine having at least anintake port, the provision of an air conduit for said port, air flowcontrol means in said conduit, first Venturi means in said conduitbetween said port and said air flow control, second Venturi meanshaving-an entry opening and exit opening with a low pressure producingthroat area therebetween, said exit opening extending from the interiorof the second Venturi device into the interior of the conduit betweensaid port and said air flow control, said entry opening extending toatmosphere, a dia phragm device having a flexible diaphragm separating afirst chamber and a second chamber, tube means extending from the throatarea of said first venturi to the first chamber, tube means extendingfrom the throat area of the second venturi to the second chamber, andfuel valve means operable by movement of said separating diaphragm, saidfirst venturi'serving to produce a difierential of pressure between saidfirst and second diaphragm chambers upon movement of air through saidconduit and first venturi to said engine and thereby operate said valvemeans to allow fuel to be admitted to said engine, and said secondventuri servin to produce a differential of pressure between said secondand first diaphragm chambers upon stoppage of air movement through saidconduit to said engine and thereby operate said valve means to stop fuelpassage to said engine.

HERMAN HERSCH.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,394,615 Erwin Oct. 25, 19211,937,938 Aseltine et a1. Dec. 5, 1933 2,136,959 Winfield Nov. 15, 19382,230,311 Seymour Feb. 4, 1 941 2,295,656 Hersey et a1 Sept. 15, 19422,428,377 Morris Oct. 7, 1947 2,447,264 Beardsley Aug. 17, 1948

